Of the saint only by the scale of purity of conduct.  The position of a saint is like a sitar which has no strings.  Just as a stringless sitar is incapable of giving melodious music, similarly a person without virtue is incapable of conveying a sattvic message to society.  Purity of conduct is the certificate of saintliness. 

 1469 AD  Born to father Kaluji and mother Triptaji in a village called Talwandi (about 30-40 miles away from Lahore) in Punjab province on the occasion of Kartik Purnima, Guru Nanak Dev was a symbol of purity of conduct and synonymous.  For Guru Nanak Dev, virtue was not the utterance of the lips, but the conduct of the soul.  1539 AD  Till that means Guru Nanak Dev continued to give the message of virtue.  

He said, 'O mind!  If you have to remain hungry due to a lack of money nearby, then there is nothing to be worried about.  Worry only that you do not get immoral things done.  'Saint Guru Nanak Dev gives honest earnings.  Honesty is the foundation of virtue.  The bread earned by faith was actually a symbol of virtue and sattvic because he refused to touch the delicious dishes of the rich but dishonest like 'Malik Bhago' but made from the hard-earned money of poor but honest like 'Kirti Bhai Lali'. 

 The dry roti of millet was accepted happily considering it as sattvik and better.  The author of these lines is also of the opinion that the money earned by immoral means is such a cobra snake that keeps on biting the soul inside, whose poisonous results have to be suffered by the family/generations.  In one sentence, the family suffers, the children suffer and the generations are harassed.  Because ' karma ' never follows • Leaves.  The turbidity of the mind will be removed only when the earnings are 'true'.  

it happens.  Guru Nanak Dev has said, 'Tirath note kya Kare mal gunman in the mind', that is, if the mind is dirty, what will happen even if you take a bath at the shrine?  It also means that to remove the filth of the mind, be virtuous.  The filth of the mind will be washed away with the soap of virtue, that is, the purity of conduct will come, then automatically you will get the fruit of the pilgrimage (If the mind is healed, then the Ganges in the pot).  Sant Guru Nanak Dev has described the purification of body and mind by means of peace, good deeds, contentment, reverence and Satsang etc. is necessary for virtue.